// ******************************************************************
// Copyright � 2015-2018 nventive inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// ******************************************************************
using System;
using System.Collections.Generic;

namespace Uno.Collections
{
    public class LazyList<T> : ListDecorator<T>
    {
        public LazyList(Func<IList<T>> factory)
            : base(null)
        {
            Factory = factory;
        }

        public Func<IList<T>> Factory { get; private set; }

        public override ICollection<T> Target
        {
            get
            {
                var list = base.Target;

                if (list == null)
                {
                    Target = list = Factory();
                }

                return list;
            }
            set { base.Target = value; }
        }
    }
}